81d402216d
This will speed up the common case where a Key is deserialized from disk, but is then serialized to build eg, the path to the annex object. Previously attempted in4536c93bb2and reverted in96aba8eff7. The problems mentioned in the latter commit are addressed now: Read/Show of KeyData is backwards-compatible with Read/Show of Key from before this change, so Types.Distribution will keep working. The Eq instance is fixed. Also, Key has smart constructors, avoiding needing to remember to update the cached serialization. Used git-annex benchmark: find is 7% faster whereis is 3% faster get when all files are already present is 5% faster Generally, the benchmarks are running 0.1 seconds faster per 2000 files, on a ram disk in my laptop.
45 lines
1.4 KiB
Haskell
45 lines
1.4 KiB
Haskell
{- git-annex .variant files for automatic merge conflict resolution
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-
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- Copyright 2014 Joey Hess <id@joeyh.name>
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-
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- Licensed under the GNU AGPL version 3 or higher.
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-}
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module Annex.VariantFile where
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import Annex.Common
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import Utility.Hash
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import qualified Data.ByteString as S
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variantMarker :: String
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variantMarker = ".variant-"
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mkVariant :: FilePath -> String -> FilePath
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mkVariant file variant = takeDirectory file
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</> dropExtension (takeFileName file)
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++ variantMarker ++ variant
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++ takeExtension file
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{- The filename to use when resolving a conflicted merge of a file,
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- that points to a key.
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-
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- Something derived from the key needs to be included in the filename,
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- but rather than exposing the whole key to the user, a very weak hash
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- is used. There is a very real, although still unlikely, chance of
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- conflicts using this hash.
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-
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- In the event that there is a conflict with the filename generated
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- for some other key, that conflict will itself be handled by the
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- conflicted merge resolution code. That case is detected, and the full
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- key is used in the filename.
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-}
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variantFile :: FilePath -> Key -> FilePath
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variantFile file key
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| doubleconflict = mkVariant file (keyFile key)
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| otherwise = mkVariant file (shortHash $ serializeKey' key)
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where
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doubleconflict = variantMarker `isInfixOf` file
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shortHash :: S.ByteString -> String
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shortHash = take 4 . show . md5s
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